Mode 4 serial data

[Dave Hempstead]

Hi Ross,
   Mode 4 puts the engine into a diagnostic mode.  It allows the user to
set a bunch
of parameters (like TPS, etc) to specific values (sent over the ALDL).

   Mode 2 dumps do take awhile.  My scanner program used to support this
mode.
However,  in my PCM, mode 2 dumps can dump every address in the PCM
EXCEPT address 0xFFFF.  Therefore, you cannot use this data to reprogram

your PCM (unless you try to guess at the contents of 0xFFFF).
   The real way to dump the PCM contents is to download code that
specifically
does this.
   I don't know how the newer PCM's do this via OBD-II.  I'd love to
learn.

   Who knows what the 'standard id' is for each 'box' on the line??  I'd
like
to learn this too.  I know the PCM is $F4, and think the ABS is $F9.
What
are the others?????????

Dave Hempstead